A fastener device of the kind initially mentioned is known from a number of publications. European Patent 0 539 793, for example, discloses a nut element which can be introduced in a form-locked and force-transmitting manner into a component, in particular into a sheet metal part, by means of a method termed clamping hole riveting. Piercing bolts are also known from German patents P 30 03 908 and P 34 47 006 which can be inserted in a self-piercing manner into a component in the form of a sheet metal part, with the features of shape, which form the so-called piercing and riveting section of the bolt element, being provided on the side of the head remote from the shaft part of the bolt element, so that after the bolt element has been inserted into a component from one side, the shaft part of the bolt element extends away from the sheet metal part on this side.
Bolt elements are also known which can be inserted into a pre-punched component and can be fastened to the component in the region directly below the head of the bolt element by means of a joint which can be made by a forming technique. Such bolt elements are described, for example, in German Patent Application P 44 10 475. However, they can also be executed in a self-piercing design such as is set forth in the applicant's German Patent Application 195 35 537.7. With such so-called EBF bolts or self-piercing EBF bolts, once the joint to the component has been made, the head of the bolt element is arranged on the one side of the component and the shaft part with thread is located on the other side of the component.
Generally, all elements from the product range of Profil Verbindungstechnik GmbH & Co. KG, i.e. RND, RSN, HI, RSF, RSK, UM, RSU and FUN nut elements as well as EBF, SBK and SBF bolt elements, are suitable for the present invention. Almost all fastener elements which are known in the prior art for forming a joint by a forming technique to a component or a sheet metal part can also be used without any problem for the purposes of the present invention.
Reference is made to the following German patents and patent applications with respect to further information on the different fastener elements from the Profil company which are suitable for use in the present invention and with respect to the methods of manufacture and insertion which can be used: P 34 04 118, P 30 03 908, P 34 46 978, P 34 47 006, P 35 24 306, P 36 10 675, P 38 35 566, P 34 48 219, P 42 14 717, P 35 83663, P 4231 715, P 3439 583, P 68 908 903, P 691 01 491, P 44 10 475, P 42 112 78, P 42 11 276, P 43 10 953, P 44 204 26, P 44 29 737, 196 00 290.7, 195 35 537, 195 30 466, P 44 40 620, 196 47 831 and P 29 47 179.2. A number of various other industrial property rights of Profil Verbindungstechnik GmbH & Co. KG could also be named here.
All the above fastener elements are fastener elements which can be inserted into a sheet metal part, or optionally into a plurality of sheet metal parts contacting one another, and which then permit the screwing on of a further sheet metal part. The screwing on is carried out by means of a bolt or a nut which is screwed into or onto a fastener element made as a nut element or as a bolt respectively.
There is an increasing need in the sheet metal processing industry, but also in other industries, to screw a highly loaded component such as a mounting for an axle or a door hinge of an automobile to another component, for example a hollow section made up of a plurality of sheet metal parts, in such a way that an extremely stable attachment results. Such stable attachments can only be achieved for the production of such hollow parts with a greater amount of effort, particularly in view of the trend towards thin sheet metals.
One possibility to improve the stability of the mounting is to insert a spacer tube between two components spaced from one another and to achieve the screw connection via the spacer tube. The two sheet metal parts coupled via the spacer tube reinforce one another in this way. Furthermore, movements of the spacer tube with respect to the one or the other sheet metal part are suppressed by the attachment of the spacer tube at both ends, which is of benefit to the stability of the connection to the screw-on part.
Such spacer tube connections, see, for example, DE C 39 36 376, have, however, previously only been realized using welding processes. However, this produces the disadvantage that the positional accuracy of the metal sheets relative to one another is very low and the, as a rule, high dynamic permanent stresses cannot be borne without difficulty by the welded joints.
Furthermore, the heat development during a welding process is not compatible with the strength requirements when high-strength, alloyed metal sheets are used.
It is the object of the present invention to provide a fastener device which can be used without difficulty in conventional sheet metal working, which can be realized at low cost and which allows a very stable attachment of a third component to a composite part comprising the first and second components and the fastener device.